The use of pedals can have benefits. But it is NOT the fastest, or most natural way to do an embouchure change.
Lip buzzing (no mouthpiece just the lips) will ALLOW the lips to assume the position that THEY want to be in when they play. Learning to play the way your body naturally wants to will really improve your playing. You no longer FIGHT your bodies natural tendencies but learn to work with them.
To learn to turn a lip buzz into a real embouchure work on sneaking the buzz onto the horn. Buzz your lips and while buzzing gently bring the horn into playing position. This will produce a note through your horn. Continue to play until you need a breath. Then remove the horn from your lips, take a breath, buzz and sneak it back into position. Do this for every breath until the embouchure setting becomes YOUR setting.
Finally do NOT believe anyone who tells you that an embouchure change is easy. They are either trying to mislead you or they don’t know what they are saying. An embouchure change is for when there is a serious problem that you can NOT overcome. The one I listed is the fastest. But it takes 2 – 4 weeks to learn the embouchure and months to retrain muscles . Pedals can take YEARS.
I can honestly tell you that for me lip buzzing and using almost NO tongue arch beat playing pedals 10-1. Endurance shot through the roof, range increased 2 octaves + in a couple of weeks. Mouthpiece pressure dropped off also. (I had an A over high c with Systematic approach). Practice time was cut in half and a couple of days off the horn makes NO difference in playing.
No the lips do not HAVE to buzz but if they do the endurance, range and resonance all increase dramatically. Take Bobby Shew he teaches a modified lip buzzing using the fingers instead of the mouthpiece. I really would be surprised if Claude didn’t actually buzz as he played. I know of several people who said they didn’t buzz because if they removed the mouthpiece they stopped. That has to do with the sudden loss of backpressure they tried to compensate by making a larger lip aperture and stop the buzz themselves.